1. Field of the Invention
This invention generally relates to apparatus for allowing selective fluid communication between an anesthetic agent container and an anesthetic vaporizer. More particularly, the invention relates to an adapter mountable on an anesthetic agent container for connecting the container to an inlet port of an anesthetic vaporizer.
2. Description of Related Art
During surgical procedures, it often is necessary to anesthetize a patient. One method of delivering anesthetic is in a gaseous form, which is inhaled by the patient. For the safety of the patient and medical personnel, the anesthetic agent is typically transported in liquid form in a suitable container. Known liquid anesthetics include halothane, isoflurane, and sevoflurane. The liquid anesthetic is ultimately dispensed into an anesthetic vaporizer, which mixes the liquid anesthetic agent with a carrier gas, such as oxygen or nitrous oxide, that is inhalable by a patient.
Liquid anesthetics are relatively volatile and can evaporate at room temperature. Before it can be used, the anesthetic agent must be transferred from a first closed environment, e.g., a container or bottle, to a second closed environment, e.g., a vaporizer. In order to transfer the anesthetic, it is well-known to provide a vaporizer inlet port with a valving system that is selectively openable to allow a liquid anesthetic agent to be poured into an internal sump of the vaporizer. Such valving systems for sevoflurane are described in U.S. Pat. No. 5,381,836 to Braatz et al. and in U.S. Pat. No. 5,505,236 to Grabenkort et al., which are hereby incorporated herein by reference. The system described in Grabenkort et al. is understood to be commercially referred to as the Quik-Fil™ system of Abbott Laboratories, and similar systems can be found in numerous vaporizers, such as the Sevotec 5™ vaporizer from Datex-Ohmeda, Inc.
The above patents describe an arrangement in which the anesthetic agent container is provided with an integral or separate adapter with a valving system configured to mate with the vaporizer valving system for allowing selective dispensing of the liquid anesthetic contained therein. To transfer anesthetic agent from the container to the vaporizer, the adapter is inserted into the vaporizer inlet port. As a result of competing biasing springs in the adapter and the vaporizer, insertion of the adapter results in sequential opening of a valve associated with the inlet port of the vaporizer and a valve associated with the adapter, allowing the liquid anesthetic agent to flow out of the container, through the adapter, and into the vaporizer sump. Thereafter, the adapter and container are removed from the vaporizer inlet port and the adapter valving system and vaporizer valving system are separately, automatically closed by the biasing springs.
One potential drawback with the filling systems of Braatz et al. and Grabenkort et al. is that they rely on the proper selection and quality control of competing biasing springs of different strength in the adapter and vaporizer valving systems in order to cause the preferred sequential opening of the vaporizer before the adapter. Of course, this system does not work properly if the springs, through lack of manufacturing quality control or for other reasons, are not of the proper strength. Accordingly, attempts have been made to provide alternative filling systems. One example of an alternative filling system is described in U.S. Pat. No. 6,585,016 to Falligant et al., which is hereby incorporated herein by reference. Variations of the Falligant filling system are described in U.S. Pat. Nos. 6,817,390 and 6,929,041, both to Falligant et al. and both of which are hereby incorporated herein by reference. These systems generally employ a fixed central rod or finger in the vaporizer inlet opening to directly contact a valve head in the adapter and force it open when the adapter is inserted into the vaporizer inlet opening.
While the above filling systems eliminate the need to properly select or calibrate the biasing springs, one drawback with them is that they require a different vaporizer valving system that may not be compatible with prior competing-spring systems and may result in confusion in the marketplace and among anesthesiologists or technicians.
As set forth in more detail below, the present invention provides an improved adapter that does not suffer from one or more of the above drawbacks.